Process for making spiral tubing by electric welding



R. STRESAU Nov. 17, 1931.

PROCESS FOR MAKING SPIRAL TUBING BY ELECTRIC WELDING 3 Sheets-Sheet 1Original Filed March 26, 1923 INVENTOR.

Richard Sfresau,

A TTORNE Y.

Nov. 17, 1931.

R. STRESAU PROCESS FOR IAKING SPIRAL TUBING BY ELECTRIC WELDING' 3Sheets-Sheet 2 Original Filed March 26, 1923 .Q |l 9 n J .N@ E I um mmvs Q o o A TTORNEYO Nov. 17, 1931. R. STRESAU 1,332,059

PROCESS I'OR MAKING SPIRAL TUBING BY ELECTRIC WELDING Original FiledMarch 26, 1923 3 Sheets-Sheet S x i :,f I INVENTOR. E: L m Richard5Tre5au i BY ii mzm.

A TTORNE Y.

Patented Nov. 17, 1931 UNITED STATES PATENT OFFICE- BIOEABD STRESAU, OFWAUWATOSA, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 AMERICANROLLING- MILLCOMPANY, OEMIDDLETOWN, OHIOQA CORPORATION OF OHIO PROCESSFOR MAKING SPIRAL TUBING BY ELECTRIO'WELDING Originalapplicatlon filedItarch 26, 1923, Serial No. 627,599. Divided and this application filedFebruary 9, 1925. Serial No. 8,071. 1

This application is a division of my application filed March 26, 1923,Serial'No. 627,599, for the apparatus employed in carrying out thepresent invention.

My invention relates to an improved process specifically applicable tomaking spi rally welded pipes and tubes, but is susceptible of generalapplication to the manufacture of spirally Welded tubular articles.

tively feeding a flat strip of sheet metal into tube forming devices andautomatically forming such strip into a spirally wound tube with theconvolutions extending in the same lane While under oin such feedin P ge g movement. and at the same time the abutting or contiguous edges ofthe spirally wound strip, as the latter is formed into a tube, areunited by electric arc welding along the spiral 29 line, so as toconstitute an integral tubular structure with a finished exteriorsurface.

The invention comprises also the step of permanently connecting the rearend of one metal strip to the forward end of a succeeding strip by atransverse welding operation, so that as the first strip is consumed inthe process of converting it into tubular form,

the operation of tube forming is not interrupted but may be continuedindefinitely, by reason of the provision of means for continuing thesupply of strip material. The linear extent of the tubular product isnot therefore limited by the length of asingle strip, but the length ofstrip material available for the purposes ofmy invention isindeterminate. I

The invention comprises further the step of welding transversely of thestrip the abutting ends of the stri s in succession and with outinterruption o the tube forming operation, as well as the step ofwelding the abutting or contiguousedges of the strip during theformation of the latter into a spirally wound tube. In connection withthe transverse welding, I clamp the contiguous ends of the strips insuccession, so that the latter are held in proper position for theperformance of the transverse welding operation.

Preferably, but not necessarily, I insert The invention comprises thesteps of posi- .L-shaped chill at both thespiral and transverse weldinglines, the chill strips, which furnish additional welding material,being fused and i'ncorporatedas part of the wel edjoint in each case.The devices for supplying the chill strip to. the spiral weld areoperated in consonance with the continuously operating tube formin andspiral welding devices, while those or supplying the strip to thetransverse weld are operated periodically, and only when it becomesnecessary to unite the abutting ends of the succession of strips. i

I provide also for grinding the surplus metal away from the spiralwelding line as the tube is being formed, so that a finished and smoothexterior surface is produced during the manufacture of the tube.

My invention contemplates also an operation whereby the continuouslyformed and completed tube of indefinite length may be Other featuresresiding in my present invention will be more specifically referred tohereinafter, and the novelty of the invention will be pointed out in theappended claims.

In the drawingsattached and forming part hereof:

Figure 1 is a plan view showing the general arrangement of the devicesby means of which my invention is put into practice.

Fig. 2 is a vertical sectional view on the line 2-2, Fig. 1, lookingfrom the top of Fig. '1, in the direction of the arrows.

Fig. 3 is a vertical section transversely of the apparatus on the line3-3, Fig. 1, near the point where the spiral welding is performed.

Fig. 4 is a vertical central section taken longitudinally of the tubeforming and spiral welding means at the same point.

Fig. 5 is a rear view in elevation of the traveling mechanism employedfor transversely welding the contiguous or abutting ends of thesuccession of metal strips, the

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said view looking to the right of Fig. 1 and the left of Fig. 2. a

Fig. 6 is an enlarged view in elevation corresponding to the view at theleft of Fig. 2,

8-8, Fig. 1, showing the arrangement of the radially adjustable pressurepoints which direct the metal strip tion.

In the drawings, the frame 10 supports the table 11, over which passesthe flat metal strip uring its tubular forma- 12, which is to beautomatically converted into tubular form by spiral winding, the abuttinedges of the said strip being always disposed in spiral formation, andunited by electric arc welding along the spiral line of such winding.Journaled in bearings in the frame 10 are positively acting,continuously driven feed rollers 13 and 14, geared so as to rotate inunison, and engaging the opposite surfaces of the strip 12,-so as toadvance the strip into the tube forming devices, whereby the strip isconverted into its tubular form with a spiral seam. The operation of thecontinuously driven rollers 13 and 14 is such that the metal strip 12 isadvanced at a uniform rate of speed by positive action, and is made toassume its tubular form under the pressure exerted by the feed rollers.

In order that the fiat metal strip thus fed through the machine may beconverted into an elongated or wide annulus of spiral construction withits edges in proximity and the convolutions thereof in the samelongitudinal plane, I arrange on a bracket 15 carried by the frame 10, atubular casing or shell 16, the interior diameter of which is equal tothe exterior diameter of the tube to be produced. Adjustably mounted atone end within the tubular casing 16, but in fixed relation thereto, isa hollow cylindrical'mandrel 17, the adj acent tube shaping surfaces ofthe casing 16 and the mandrel 17 being concentrically positioned withrespect to each other, but separated by an open circular spacesutlicient only to permit the free passage of the strip 12 through thesaid space, so as to conform the convolutions of the strip into theexact annular state desired, and prevent overlapping of the edges. I

As shown in Fig. 2, the bracket15""'at"its outer end is curved upwardlyand returned so as to form a yoke and provide vertically disposedaligned bearings for the journals 18' and 19, formed upon the casing 16.The casing 16 with its adj unctive devices may therefore be rotated uponits vertical axis so as to be adjusted in a horizontal plane and set atany divergent angle with relation to the line of movement of the strip12. By means of this provision for adjustment, the edges of the strip atthe time of completing the spiral tubular formation may be given suchpitch and be brought into such exact proximity and relation thatconditions conducive to a most favorable and effective welding operationmay be attained. A tie bar 20, which may be conveniently formed as aturn buckle, is connected at one end with an car on the swiveled casing16, and at the other end with an car on the frame 10, whereby thedesired adjustment of. the casinmay be effected with precision, andtherea ter maintained during the operation of the apparatus. Bolts 21,21, passing through a web 22 extended from the to of the casing 16, andthreaded into the ta 1e 11 also serve to further maintain the casing 16in its adjusted position. A guard plate 23 is mounted on the table 11,just in advance of the feedin rollers 13 and 14, a channel being formedbetween the table and the web 22 and guard plate 23, for insuring theproper advancing movement of the metal strip 12, thus overcoming anytendency of the late to buckle under the force exerted by t 1e feedrollers and resisted by the tube shaping elements of the apparatus.

The casing 16 is provided with a radial opening which is coincident withthe meeting line of the edges of the metal strip in the formation of thefirst convolution thereof. Projecting through the said opening andslightly into the interior of the casing, is an adjusted thin metallicspacer 24, having a thickness which will produce and maintain a slightseparation of the edges of the strip as the convolution is formed, thepurpose in producing such separation of the edges being to enable theinsertion of a welding and cooling strip 25, into the welding groovefrom the inside of the tube. Such welding strip 25 is rolled into theform of a .L, the upstanding stem of which is forced into the spaceseparating the convolutions of the pipe just in advance of the spacer24, so that such welding strip may be fused into the joint in thewelding operation, which commences immediately,and becomea permanentpart of the welded joint; In'addition to its purpose in supplyingad'ditional metal for the welded joint, the said strip acts as a backingplate which prevents" a fusion of the weld with the stationary mandrel17 or burining the metal atthewelding line. In the welding opera- ,tion,the stem of the strip 25 is fused with the edges of the coiled strip 12and incorporated into the weld, while the base or lower flat surfaceforming the bottom of the strip lies interiorlv of the tube against thespiral joint formed therein.

In order to feed the welding strip 25 as welding line, and which isadapted to bear against the inner side of the tube at the point wherethe welding is performed, to hold the welding strip 25 in properposition with respect to the-space separating the convolutions of thestrip 12 and edges to be welded. An expansion spring 29 surrounds thepost 26 and exerts a pressure on the sleeve 27, which will be sufiicientto engage the periphery of the feed wheel 28 with the interior of thetube,

through the strip 25, such engagement being frictional in a degreeaiwliich' will effect the coincident rotation of thenyheel 28with that of thetube as the latter i being formed. The welding strip is e'ntere themandrel 17, that isf'the" end appearing at the top of Fig. 1. and .isdirectedto the wheel 28 by means of a tubular guide 30, and;;

is automatically fed or drawn into position by the conjoint rotation:of'the feed wheel-28 and the spiral tube which is "beingformed;-

The casing 16 is cutaway for a portion of its circumference so as'toform an opening or recess 31, the sides of which may be parallel to thetraveling welding line. The purpose of the saidrecess 31 is to provide aclearance in which the weldrod A may enter, so as to perform the weldinoperation upon the contiguous edges of tlie spirally wound strip. Thefeeding wheel 28 is located immediately underneath the recess 31. Thetubular mll1.

drel 17 is clamped at its rear or inoperative end in the casing 16 bymeans of a bolt 32 which bridges an axially extending slit in the casing16, so that the said mandrel may be accurate] adjusted and maintained asto its position in the casing.

The table 11 'may be provided with longitudinal guides 33, 33, forproperly directing the metal strip 12 into the apparatus. A strip 12upon being laid upon the feed table 11 is entered between the feedingrollers 13 and 14, and thereafter positively fed by such rollers intothe tube forming mechanism, to be converted into a spirall wound tube,and welded to form an integra structure in the manner before described.As a result of the great pressure exerted by the feeding rollers uponthe metal strip, the latter is forced through the tube forming devicesby a positive action, and caused to follow the contour of the casing andthe mandrel. The latter being set at the desire divergent angle withrelation to the line of movement of the strip, it follows from thearrangement that the metal strip will assume the annular form of thetube, with the convolutions extending in the same plane and with theedges in such contiguous or v. at ftlie open end ofproximate relation,that the welding of such edges may be easily and completely effected.

In Fig. 8 I have shown an arrangement of radially adjustabledevices'designed to bear upon the advancing end of the metal strip 11,and to impart thereto the desired initial curvature to facilitatepassage through the tube forming devices. The points are hardened so asto resist wear, and two of them, indicated 60 and 61, are arranged inradial openings formed in the casing or shell 16, being held in positionby means of set screws threaded into the casing. Shims ma be insertedbetween the casing and the heads of the points 60 and 61 to secure exactadjustment. The third point 62 is arranged in a similar manner in anopening formed in the mandrel 17, and adjustment thereof to thedesiredposition is effected by means of a set screw threaded through a bossformed interiorly of the mandrel.

Welding devices are now so well known that it isnot considered necessaryto illustrate the arrangement of the same in the present connection, butsuch devices may be supported upon the casing 16 and partici ate inspiralwelding devices, will always be traversed by the Welding line inthe rotation of the tube. I prefer to use a destructible weldrod, andfto incorporate the molten metal flowingtherefro'm in the fusion of theedges of the-spirally wound strip, together with the welding strip 25.But an ordinary electrode may be used to conduct the welding current andproduce the arc in the welding operation, instead of a fusible weldrod,such as is preferably used by reason of the more sat isfactory resultsattained by the latter.

As the rear end of the first strip 12 ap proaches the feed rollers, Ibring into conjunction with it the forward'end of a second strip, and bya transverse Welding operation upon the meeting ends of the two strips,unite them into a single length, so as to enable the apparatus tooperate continuously in producing the tube. The transverse weldingapparatus is adapted to have a longitudinal movement with the metalstrips, and to maintain the weldrod in a fixed position with relation tohe transverse welding line. The transverse welding devices are connectedor coupled to the strip at the right moment so as to permit forwardmovement therewith, while the point of the weldrod is traversing thewelding line.

The transverse welding devices are mount ed in a frame 34: supported onrollers which movev over longitudinal tracks 35 fixed on the framelOadjacent the table 11, the frame 34 being normally held in itsretracted position by means of a weight 36, or other means, but free tomove forwardly when the resistance of the weight is overcome by theclamping action exerted upon the moving strip 12.

An oscillating spacer 37, which may be formed as a disc with oppositeprojections thereon, is pivoted in the frame 34 below the surface of thetable 11, the axis of the spacer being parallel with the length of thetable.

The said s acer is rotated in one direction by means of a spring 38,coiled about the axis thereof, and serving to bring the upper projectionof the spacer above the surface of the table. The presence of a metalstrip upon the table 11 will depress the upper projection on the spacerbelow the level of the table, and hold it in that position while thesaid strip is being carried forward by the feeding rolls 13 and 14.When'the rear end of the strip clears the spacer 37, the spring 38 willact to effect reverse rotation as before described. In the rotation ofthe spacer under the influence of the spring, the lower projection onthe spacer will strike the end of a centrally pivoted lever 39, theother end of which engages a spring contact 40 and closes an electriccircuit, which includes the coil-of a magnetically operated clamp 41.The core of the latter, is provided with a lateral extension 42 which'isadapted in the energization of the coil to engage the forwardly movingstrip 12. Thereupon, longitudinal movement of the frame 34 carrying thetransverse welding destrip, the motor operating the rollers 44 beingenergized in the closing of the clamping circuit.

The frame 34 also carries devices which are designed to feed a sectionof welding strip or chill similar in formation to that used inperforming the spiral weld upon the tubular structure before described,the said chill strip being adapted to be positioned between the meetingends of the two strips 12, as shown in Fig. 6, a groove being formed inthe table of the frame 34, for guidance thereof. A motor 45 mounted uponan extension of the frame 34, and in the circuit of the clamp 41,

" is operated to drive through a worm and gear,

the chill strip feeding rollers 46, the latter giving forward movementto a ram or driver 47 which will push the chill strip into its positionbetween the contiguous ends of the :.trips 12. The end of the chillstrip in the movement toward final position, will rotate the spacer 37in the opposite direction against the force of the spring 38, thusbreaking the circuit at 40, although effectiveness of the latter ismaintained through the shunt before described. The forward end of thesecond strip 12 is in the meantime being advanced into proximity withthe rear end of the first strip 12, so as to leave a nalrow spacebetween such ends, which is entered by the stem of the chill strip, thecontinued movement of the second strip 12 closing the space between theends of the strips 12 and engaging the chill strip between such ends.When the second strip 12 has completed its forward movement, the rollers44 will slip over the surface of the plate.

. During the final movement of the chill strip 1nto position between theends of the tube forming strips 12, the end of the chill strip willcontaetwith a projection on a disc 48 mounted on the frame 34, so as tooscillate in the manner described with reference to the spacer 37, thesaid disc 48 being rotated to a normally inoperative position by meansof a spring coiled about the axis thereof. Rotation of the disc 48 inthe other direction in the final movement of the chill strip will causea lower projection on the disc 48 to pass the switch 49 and momentarilyclose a circuit. Such closure will'energize the coil of a magnetic clamp50, the core of which is provided with a lateral extension 51 which isadapted to engage and hold down the forward end of the second strip 12,so that both strips are now clamped to the frame 34 of the transversewelding devices. The movement of the core of the clamp closes a shuntcircuit at 52, so that the clamping action is maintained during thetransverse welding operation, even though the circuit be broken at 49,through relaxation of the engagement of the end of the chill strip withthe disc 48. Clamps 41 and 50 are provided at each side of the line oftravel of the strips 12.

The upper part ofthe frame 34 supports tracks 53, along which travel ahead 54 carrying the transverse welding devices, the head 54 being motoractuated to traverse the welding line, and at the completion of theWelding operation is returned to the initial position by means of acounterweight 55. The transverse welding devices carried by the head 54,and exemplified by the weldrod B, may be of any suitable construction,such as will serve to feed a fusible weldrod in the ratio of theconsumption of the latter while the welding is taking place. A wiper 57adapted to interrupt the several feeding movements and open the circuitof clamp 41 at 58, to deenergize the coil of the said clamp, and a wiper59, adapted likewise to break the weld ing circuit at 63, and tode-energize the clamping coil 50 are carried by the welding head 54, andoperate at the moment that the weldrod 56 has completed its movementover the welding line. The parts assume their normal inoperativepositions, in which they remain until the time arrives for makinganother transverse weld, when the operations are repeated. In thiswelding operation, I may use an electrode in conducting the arcingcurrent, but a fusible weldrod is preferable.

ratus in such a length as to present a problem in taking care of theoutputin an ellicient manner. In order to meet the exigency, I haveinstalled means whereby the spirally welded pipe during its productionmay be cut transversely upon circumferential lines, so as to producetubular sections of the desired lengths. Such cutting of the pipe iseffected automatically without interruption of the pipe forming andwelding operations. In order to achieve the purpose of this feature ofmy invention, I arrange in a position parallel to the path of movementof the pipe, a traveling carriage 65 movable on a track 66, the saidcarriage being provided with a counterweight 67 to hold it in retractedposition, and with a stop 68 which is engaged by the forward edge of thepipe in the outward movement of the length thereof.

Mounted also on the carriage is a bracket 69 which supports a torch 70,to which a suitable conductor may lead for conveying the cambustionelement to the line on which the pipe is to be severed. The stop 68maybe in the form of a roller, mounted for rotation upon a post attachedto the frame of the carriage 65, so that in the advancing movement ofthe pipe section the said roller will be engaged by the forward edgethereof as the pipe is rotated, so as to advance the carriage in thesame ratio. Therefore, the flame of the torch will be maintained inrelatively fixed position in a line about the circumference of the pipe.With each revolution of the pipe a section thereof will be severed onthe circumferential line upon which the flame of the torch plays. Uponremoval of the sevcred section, the carriage 65 will return to itsrearward position with the stop 68 in engage ment with the newly formedfront edge of the advancing pipe. The carriage 65 may be made to controlthe flow of the burning mixture by convenient means as desired, andwhich it is not necessary to illustrate in'this connection. Therelatively slow rate of rotation of the pipe during its formation,enables the flame to make a comparatively clean cut on the line ofseverance.

While the apparatusas constructed performs the spiral welding operationcompletely and satisfactorily, it occurs occasionally that a slightexcess of metal is deposited by the fusing weldrod upon the spiralwelding line, rouggghening the outer surface of the tube. In order toremove such excess of metal and turn out the spirally welded pipe with asmooth exterior, I mount a motor 775 carrying a grinding wheel 76, whichis posi tioned so as to operate over and upon the welded joint, andgrind away any surplus material which may have been deposited thereon.Provision, for the radial adjustment of the grinding wheel with relationto the exterior surface of the ipe should be made, in order that theworh may be most efiiciently performed.

In constructing the tube forming devices, I have found that the bestresults can be attained by the use of the mandrel and casing described,which are spaced concentrically from each other a distance which ismerely suflicient to permit the free passage of the strip through thetube forming devices. By following this arrangement the convolutions asdesired, and over-lapping of the edges thereof is prevented. Theposition of the spacer 24: determines the location of the spiral weldingline, by lining up the edges with the point of the weldrod. Operatingtogether, the devices referred to insure the proper presentation of theedges of the strip in correct position for welding. The path of thestrip in assuming its circular course is therefore fixed, and thematerial is firmly held at the welding line, so that any warping ordistortion in the formation is obviated. The resulting product istherefore exuded from the forming device with a perfect contour in sofar as its longitudinal planes are involved.

But owing to the tendency of the metal strip, under the pressure exertedby the feed ing rollers, to closely follow the interior outline of thecasing 16, and until it reaches the welding point, it is not necessaryin allcases to employ a mandrel as a part of the tube forming device,for the reason that the tube can be produced with the same degree ofperfection by an apparatus from which the mandrel has been omitted.However, the mandrel forms a convenient element of the con struction, inthat it affords a support for some necessary adjuncts.

The speed at which the apparatus illustrated may be operated in itsentirety is determined by the time within which the spiral weldingoperation can be performed. I The strip feeding rollers and thetransverse welding devices for connecting the ends of a succession ofstrips, the latter devices having for their purpose to constitute acontinuous supply of tube forming material, are capable of operating ata much greater relative speed in the performance of their functions. Imay in some instances dispense with the spiral welding devices as a partof the equipment of the tube forming apparatus. This will enable a veryrapid production of the tube to be made, which in the forming operationmay be severed int-o sections, as before described, with ample time forthe transverse welding operations. Such sections may then be distributedto a plurality of machines constructed especially to complete thetubular structures by welding along the spiral lines thereof, in thetime required for the slower operation. By this means, a greater outputcan be secured than is possible in a single completely equipped tubeforming and welding apparatus.

Having thus described my invention, what I claim and desire to secure byLetters Patent of the United. States, is: r

1. The method of manufacturing spirally welded pipe which comprises thesimultaneous automatic correlated operations of electrically weldingflat strips of sheet metal end to end, progressively converting thecontinuous strip so provided into a spirally wound pipe with theconvolutions thereof in longitudinal alignment and the edges thereof inspiral alignment, inserting a fusible welding strip between said edges,and electrically welding said edges to form an integral tubularstructure wherein said welding insert is fused and integrallyincorporated inthe Welded seam.

2. The method of manufacturing spirally welded pipe of definitepredetermined lengths which comprises the simultaneous automaticcorrelated operations of progressively converting a flat strip of sheetmetal of indefinite length into a spirally wound pipe with theconrolutions thereof in longitudinal aligmnei'it and the edges thereofin spiral alignment, inserting a fusible welding strip between saidedges, electrically Welding said edges'to form an integral tubularstructure wherein said inserted Welding strip is fused and integrallyincorporated in the welded seam, and severing predetermined definitelengths of pipe from saidtubular structure as the same is progressivelydischarged from the welding operation.

In testimony whereof I have signed my name at Milwaukee this 22nd day ofJ anuary, 1925. S

R. TRESAU.

